The present invention relates to processing of data that is received or to be transmitted through a serial bus. Particularly, this invention relates to recording and reproducing data that is input through a serial bus, and also outputting the video data through the same bus in conformity with the IEEE (Institute of Electrical and Electronics Engineers) 1394 standards. This serial bus is called 1394 serial bus hereinafter.
Video tape recorders (VTRs) are well known audio and video equipment that encode video signals under the DV (Digital Video) standards defined in the IEC (International Electrotechnical Commission) 61883 standards, and outputs the encoded video signals through the 1394 serial bus.
The DV standards define the SD (Standard Definition) mode and HD (High Definition) mode. The SD mode offers recording and reproduction of video signals having definition, such as, NTSC (National Television System Committee) video signals. The HD mode offers recording and reproduction of video signals, such as, high vision signals. However, in the DV standards, VTRs for the SD mode only have been on the market.
The encoding processing under the DV standards limits the amount of encoded video signals per frame within a predetermined amount. The SD mode thus defines the fixed recording rate that is 25 Mbps for recording the encoded video signals on a magnetic tape.
The encoded video signals are output through the 1394 serial bus per packet under the DV standards after the transmission band is allocated in accordance with the recording rate for recording the encoded signals. In detail, the IEC 61883 standards define the plug control to store information needed for the transmission band into addresses that are accessible through the 1394 serial bus. The transmission band is then allocated using the information.
The amount of video signals varies when processed by VTRs at different data rates, and hence several transmission bands are also required on the 1394 serial bus in accordance with the different data rates.
For example, the packet size for an MPEG (Moving Picture Coding Experts Group) transport stream through the 1394 serial bus varies according to the data rates. This transport stream is called MPEG2TS hereinafter.
The wider the transmission band is allocated for the MPEG2TS, the more unnecessary bus resources are used. On the other hand, the narrower the transmission band, the more unstable is the data transmission due to violation of the communication protocols.
Furthermore, a user has to set the data recording mode for each input MPEG2TS, which is a cumbersome operation.
A purpose of the present invention is to provide an apparatus and a method of processing data that is received or to be transmitted through a serial bus, that achieve effective usage of bus resources.
Another purpose of the present invention is to provide an apparatus and a method of recording and reproduction of data that is received or to be transmitted through a serial bus, that achieve effective usage of bus resources with no user recording mode setting.
The present invention provides a signal processing apparatus having: a processor to encode an input signal at a predetermined data rate to generate encoded data; and a digital interface to allocate a transmission band for the encoded data based on the data rate for transmitting the encoded data through a serial bus.
Furthermore, the present invention provides a signal processing apparatus having: a digital interface to detect a transmission band of data input through a serial bus; and a processor to decode the input data based on the transmission band for outputting a decoded signal.
Moreover, the present invention provides a recording and reproducing apparatus having: a digital interface to transmit or receive data through a serial bus, the interface allocating a transmission band before data transmission; a recording and reproducing section to record and reproduce the data at least in one of a plurality of recording modes for different recording rates; and a controller to control the interface for changing the allocated transmission band in accordance with the recording mode for the data reproduced by the recording and reproducing section.
The present invention also provides a recording and reproducing apparatus having: a digital interface to transmit or receive data through a serial bus in a predetermined transmission band; a recording and reproducing section to record and reproduce the data at least in one of a plurality of recording modes for different recording rates; and a controller to control the recording and reproducing section for selecting one of the recording modes in accordance with the transmission band of the data received by the interface.
The present invention further provides a method of signal processing. An input signal is encoded at a predetermined data rate to generate encoded data. A transmission band is allocated for the encoded data based on the data rate for transmitting the encoded data through a serial bus.
Moreover, the present invention further provides a method of signal processing. A transmission band of data input through a serial bus is detected. The input data is decoded based on the transmission band for outputting a decoded signal.
The present invention also provides a method of data processing. Data is reproduced which has been recorded in a recording mode for a predetermined recording rate. A transmission band is allocated, based on the recording mode, for transmitting the data through a serial bus.
Furthermore, the present invention provides a method of data processing. Data is received which has been transmitted through a serial bus in a predetermined transmission band. One of a plurality of predetermined recording modes for different recording rates is selected in accordance with the transmission band of the received data. The data is recorded in the selected recording mode.